Optical device with movable optical module

ABSTRACT

An optical module with movable reflective mirrors is provided in the invention. The optical module, which is set in a scanner for the scanning of documents, comprises the following elements: a first carriage comprising a first reflective mirror, a lens and a photoelectric sensing device, wherein the first carriage moves along the scanning direction to scan the document to be scanned; a second carriage comprising a second reflective mirror, a lens and a photoelectric sensing device, wherein the second carriage can make relative movement corresponding to the first carriage along the scanning direction; and a third carriage comprising a third reflective mirror, a lens and an photoelectric sensing device, wherein the third carriage can make relative movement corresponding to the first carriage along the scanning direction. Of which, the first carriage is situated between the second carriage and the third carriage with the distance between the second carriage and the third carriage being fixed at a constant value during the course of scanning, while the image light of the document to be scanned forms an image on the photoelectric sensing device via the focusing of the lens after having been reflected via the first reflective mirror, the second reflective mirror, and the third reflective mirror sequentially.

This application is a continuation of U.S. patent application Ser. No.10/425,872, filed Apr. 30, 2003, entitled OPTICAL MODULE WITH MOVABLECARRIAGE HAVING MIRROR, the disclosure of which is incorporated hereinin its entirety by reference, which claims the benefit of Taiwanapplication Serial No. 91138175, filed Dec. 31, 2002.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The invention relates in general to an optical module, and moreparticularly, to an optical module with movable reflective mirrors.

2. Description of the Related Art

Of the many peripherals of a personal computer, the scanner can be saidto be essential equipment. Generally speaking, the scanners in today'smarket have only little difference in terms of function and imagescanning quality. Therefore, how to further shrink the size and volumeof a scanner to improve the convenience of use has become a focus forR&D engineers in the field of scanners.

Please refer to FIG. 1, a schematic diagram for a conventional opticalmodule. The conventional optical module 100 comprises a carriage 110 anda guiding piece 120, wherein the carriage 110 is equipped with areflective mirror set, a lens and a photoelectric sensing device (notshown in the diagram).

The carriage 110, which is coupled to the guiding piece 120, can moveback and forth along the scan direction D.

In the course of scanning, the image light 130 of the document to bescanned, the reflecting light or the penetrating light of the documentto be scanned for instance, enters into the carriage 110. The imagelight 130, reflected by the reflective mirror set composed of pluralreflective mirrors, will be focused via a lens and received by thephotoelectric sensing device.

Each reflective mirror of the reflective mirror set, the lens and thephotoelectric sensing device are all fixed in the component 110. Thepurpose is to keep both the front optical path and the rear optical pathat a fixed value such that a clear and quality scan image can beobtained. The front optical path is the path traveled by the imagelight, emitted by the document to be scanned, reflected via variousreflective mirrors, arriving at the lens lastly. The rear optical pathrefers to the path from the lens to the photoelectric sensing device.The component 10, having to accommodate all reflective mirrors, the lensand the photoelectric sensing device, is undesirably large.

It can be understood from the above disclosure that an over-sizedcomponent 110 will affect the scanner, which the component 110 isinstalled therein. The consequence is that the overall volume of thescanner cannot be effectively reduced. Moreover, a conventional scanningmodule whose back focus cannot be enlarged cannot be used to scanlarge-sized documents.

SUMMARY OF THE INVENTION

It is therefore an object of the invention to provide an optical modulewith movable reflective mirrors. The purpose is to effectively reducethe overall volume of a scanner, availing the convenience of use and thescanning of lager-sized documents.

According to the above object, an optical module with movable reflectivemirrors is provided in the present invention. The optical module, whichis set in a scanner for the scanning of documents, comprises thefollowing elements: a first carriage comprising a first reflectivemirror, a lens and a photoelectric sensing device, wherein the firstcarriage moves along the scanning direction to scan the document to bescanned; a second carriage comprising a second reflective mirror, a lensand a photoelectric sensing device, wherein the second carriage can makerelative movement corresponding to the first carriage along the scanningdirection; and a third carriage comprising a third reflective mirror, alens and an photoelectric sensing device, wherein the third carriage canmake relative movement corresponding to the first carriage along thescanning direction. Of which, the first carriage is situated between thesecond carriage and the third carriage with the distance between thesecond carriage and the third carriage being fixed at a constant valueduring the course of scanning, while the image light of the document tobe scanned forms an image on the photoelectric sensing device via thefocusing of the lens after having been reflected via the firstreflective mirror, the second reflective mirror, and the thirdreflective mirror sequentially.

Other objects, features, and advantages of the invention will becomeapparent from the following detailed description of the preferred butnon-limiting embodiments. The following description is made withreference to the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 shows a schematic diagram for a conventional optical module;

FIG. 2A shows a structural diagram for an optical module with movablereflective mirrors according to the preferred embodiment of theinvention;

FIG. 2B is a side view for FIG. 2A;

FIG. 3A is a schematic diagram illustrating relative positions betweeneach carriage corresponding to the optical module according to theinvention of FIG. 2 during scanning process one;

FIG. 3B is a schematic diagram illustrating relative positions betweeneach carriage corresponding to the optical module according to theinvention of FIG. 2 during scanning process two;

FIG. 4 shows a side view for another reflective mirror layout of theoptical module with reflective mirrors according to the preferredembodiment of the invention;

FIG. 5A is a structural diagram for the optical module with reflectivemirrors according to the preferred embodiment of the invention when backfocus is large; and

FIG. 5B is another structural diagram for the optical module withreflective mirrors according to the preferred embodiment of theinvention when back focus is large.

DETAILED DESCRIPTION OF THE INVENTION

The optical module with movable reflective mirrors according to thepresent invention differs with a conventional optical module in that theformer has three carriages while the latter has only one single butbigger carriage. The optical module according to the invention reducesthe volume of the scanner in which the carriage is accommodated. Withoutincreasing the volume of the carriage on which a lens and aphotoelectric sensing device are installed, a reflective mirror isinstalled between the lens and the photoelectric sensing device toincrease the back focus so the scanner can scan larger documents viasuch optical module.

Please refer to FIG. 2A, a structural diagram for an optical module withmovable reflective mirrors according to the preferred embodiment of theinvention, and FIG. 2B, a side view thereof. The optical module 200,which can be set in a scanner for the scanning of documents to bescanned, comprises carriages 210, 220 and 230, a guiding piece and afirmware 250.

The carriage 210 comprises a reflective mirror 212, a lens 214 and aphotoelectric sensing device 216, wherein the carriage 210, beingcoupled to the guiding piece 240, moves on the guiding piece 240 alongthe scanning direction D (the pivotal direction of the guiding piece214) to scan documents.

The carriage 220 comprises reflective mirrors 222 and 224, wherein thecarriage 220, being coupled to the guiding piece 240, makes relativemovement corresponding to the carriage 210 and moves on the guidingpiece 240 along the scanning direction D.

By the same analogy, the carriage 230, coupled to the guiding piece 240,comprises two reflective mirrors 232 and 234, makes relative movementcorresponding to the carriage 210 and moves on the guiding piece 240along the scanning direction D.

As illustrated in FIG. 2A and FIG. 2B, the image light of the documentto be scanned is reflected via reflective mirrors 212, 222, 224, 232 and234 sequentially then forms an image on the photoelectric sensing devicevia the focusing of the lens 214.

The image light 260 follows an optical characteristic of keeping thefront light path unchanged, i.e., the sum of the distance betweenreflective mirrors 222 and 212, the distance between reflective mirrors232 and 224, and the distance between the lens 214 and the reflectivemirror 234 must be kept at a fixed value. The purpose of keeping thefront light path of the image light 260 unchanged can be achieved byinstalling the carriage 210 between carriages 220 and 230, meanwhile,keeping the distance between carriages 220 and 230 at a fixed valueduring the course of scanning. A fixed distance between carriages 220and 230 can be achieved by connecting the firmware 250 between them. Asshown in the diagram, the firmware 250, passing through the carriage210, connects carriages 220 and 230. While the carriage 210 can makerelative movement corresponding to carriages 220 and 230 on the firmware250, carriages 220 and 230 can not make relative displacement due to theconnection of the firmware 250 during the course of scanning.

Please refer to FIG. 3A and FIG. 3B, schematic diagrams illustratingrelative positions between each carriage corresponding to the opticalmodule according to the invention of FIG. 2 during scanning processes.As is shown in the diagrams, all carriages 210, 220 and 230 can moveback and forth along the scanning direction D during the course ofscanning. The carriage 220 and the carriage 230 always remain a distanceof X+Y, which can be achieved by means of the firmware 250 of FIG. 2.When the distance between carriages 210 and 230 is increased from X toX+a (from FIG. 3A to FIG. 3B), the distance between carriages 10 and 220will be reduced from Y to Y−a (from FIG. 3A to FIG. 3B).

Please refer to both FIG. 2 and FIG. 4, a side view for anotherreflective mirror layout of the optical module with reflective mirrorsaccording to the preferred embodiment of the invention. Under thecircumstance of keeping the front optical path unchanged, the originaltwo-piece designed reflective mirrors 222 and 224 of the carriage 220can be replaced by a single piece reflective mirror 422 while theoriginal two-piece designed reflective mirrors 232 and 234 of thecarriage 230 can be replaced by a single piece reflective mirror 432.Such layout of reflective mirrors reduces not only the number ofreflective mirrors but also the volume of the carriage in which thereflective mirrors are installed.

Please refer to FIG. 5A and FIG. 5B, two structural diagrams for theoptical module with reflective mirrors according to the preferredembodiment of the invention when back focus is large. Normally, when alarger document is to be scanned, a larger back focus is needed. That isto say, the distance between the lens and the photoelectric sensingdevice needs to be enlarged. This can be achieved by means of thestructure shown in FIG. 5A and FIG. 5B.

Under the circumstance of not increasing the volume of the carriage 210,the locations for the lens 214 and the photoelectric sensing device 216can be adjusted with an additional reflective mirror 512 being installedon the carriage 210 as is illustrated in FIG. 5A. Another design as isshown in FIG. 5B is to install reflective mirrors 514 and 516 on the twolateral sides of the carriage 210 respectively to reflect the imagelight 260, which has been focused via the lens 216, onto thephotoelectric sensing device 216. So the back focus can be effectivelyenlarged permitting the scanning of larger documents.

In the above disclosure, the scanner can be a reflection-type imagescanner or a penetration-type image scanner; the guiding piece 240 canbe a pivotal shaft or any other elements which enable the component tomove back and forth along the scanning direction D; the firmware 250 canbe any element, which, connecting components 220 and 230, preventsrelative displacement between components 220 and 230 without impedingthe movement of the carnage 210 between components 220 and 230; thephotoelectric sensing device can be a charged coupled device (CCD) or acomplementary metal oxide semiconductor sensor (CMOS sensor).

When compared with a conventional optical module having only one largecarriage, the scanning direction of the carriage 210 according to theinvention needs only a thinner thickness because a number of reflectivemirrors have been moved to carriages 220 and 230. Being equipped withreflective mirrors only, the thickness for carriages 220 and 230 canalso be reduced. When compared with the carriage in a conventionaloptical module, all the carriages in FIG. 2B are shorter in terms of theheight while the carriages in FIG. 4 can be even shorter. With theinstallation of reflective mirrors on the carriage 210, the back focuscan be enlarged enabling the scanning of larger documents.

The optical module with movable reflective mirrors according to thepreferred embodiment of the invention is featured by the advantages ofeffectively reducing the volume of the scanner in which the opticalmodule is installed, enhancing the convenience of use and enabling thescanning of larger documents.

While the invention has been described by way of example and in terms ofa preferred embodiment, it is to be understood that the invention is notlimited thereto. On the contrary, it is intended to cover variousmodifications and similar arrangements and procedures, and the scope ofthe appended claims therefore should be accorded the broadestinterpretation so as to encompass all such modifications and similararrangements and procedures.

1. An optical device for scanning an image, wherein the optical device comprises: a first reflective surface; second reflective surface fixed relative to the first reflective surface during the scanning; and a movable component positioned between the first and second reflective surfaces and having a third reflective surface, the movable component configured to move relative to the first and second reflective surfaces during the scanning, said relative movement being along a line; wherein the movable component and the reflective surfaces are positionable such that light representing the image is focused onto a sensing device after having been reflected via the first reflective surface, the second reflective surface, and the third reflective surface.
 2. An optical device according to claim 1 further comprising a guiding piece, wherein the movable component, a structure supporting the first reflective surface, and a structure supporting the second reflective surface are individually coupled to the guiding piece and can make movement on the guiding piece respectively.
 3. An optical device according to claim 1 further comprising a firmware, wherein the firmware is used to connect a structure supporting the first reflective surface and a structure supporting the second reflective surface keeping the distance between the structures at a fixed value during the scanning.
 4. An optical device according to claim 1 further comprising a fourth reflective surface, wherein the fourth reflective surface is installed on the movable component and is used to reflect the focused light onto the sensing device.
 5. An optical device according to claim 1 further comprising a fifth reflective surface and a sixth reflective surface, wherein the fifth reflective surface and the sixth reflective surface are respectively installed on two lateral sides of the movable component and are used to reflect the focused light onto the sensing device.
 6. An optical device according to claim 1, wherein the sensing device is a charge coupled device (CCD). 7-14. (canceled)
 15. An apparatus for scanning an image, said apparatus comprising: means for positioning first and second reflective components relative to each other during scanning such that a distance between the first and second reflective surfaces is fixed at a constant value during the scanning; means for moving a third reflective component between the first and second reflective components and along a line, the movement to cause distances between the third reflective component and the other reflective components to change during the scanning; and means for focusing light representing the image on a sensing device, the light focused on the sensing device after being reflected by the first, second and third reflective components.
 16. The apparatus of claim 15 wherein the light is reflected by the third reflective component before being sequentially reflected by the first and second reflective components.
 17. The apparatus of claim 15 further comprising means for guiding movement of the first and second reflective surface relative to the apparatus.
 18. The apparatus of claim 15 further comprising means for fixing one or more additional reflective components relative to the first and second reflective components during scanning.
 19. The apparatus of claim 15 further comprising means for attaching one or more additional components to the moving means, the additional components to reflect the focused light onto the sensing device.
 20. The apparatus of claim 15 wherein both a device used to focus the light and the sensing device are attached to the moving means.
 21. An apparatus for scanning an image, the apparatus comprising: a first reflective surface; a movable component to move relative to the first reflective surface during scanning, said relative movement along a line, the movable component having attached thereto a second reflective surface and at least one of a lens and a sensing device; wherein the movable component and the reflective surfaces are positionable such that light representing the image is focused onto the sensing device after having been reflected using the reflective surfaces.
 22. The apparatus of claim 21 further comprising one or more additional reflective components located along a light path of the light, the additional reflective components attached to the movable component and fixed relative to the second reflective component during scanning.
 23. The apparatus of claim 21 further comprising one or more additional reflective components located along a light path of the light, the additional reflective components fixed relative to the first reflective component during scanning.
 24. The apparatus of claim 21 further comprising a rod to restrict movement of the first reflective component relative to a third reflective component during the scanning, wherein the rod is used to guide movement of the movable component.
 25. An apparatus for scanning an image, the apparatus comprising: means for supporting a first reflective surface; means for moving an optical module relative to the first reflective surface during scanning, the optical module having coupled thereto a second reflective component and at least one of an image sensor and a light-focusing component. wherein the optical module and the reflective surfaces are positionable such that light representing the image is focused onto the sensing device after having been reflected using the reflective surfaces.
 26. The apparatus of claim 25 wherein the moving means moves relative to the apparatus during the scanning.
 27. The apparatus of claim 26 wherein the image sensor is coupled to the optical module and moves according to movement of the optical module.
 28. The apparatus of claim 25 wherein, prior to being focused onto the sensing device, the light is reflected by the second reflective surface before being reflected by the first reflected surface.
 29. The apparatus of claim 25 wherein the second reflective component and the image sensor are coupled to the optical module and remain fixed relative to each other during the scanning.
 30. A method, comprising: configuring reflective surfaces of a scanning device to move relative to each other during scanning with said scanning device; configuring a driving component to adjust a length of a front portion of a light path during scanning with said scanning device by driving movement of at least one of the reflective surfaces, the front portion of the light path extending from a lens to at least one of the reflective surfaces.
 31. The method of claim 30 wherein the scanning device is configured to adjust the length of the light path while maintaining a length of a rear portion of the light path, the rear portion extending from the lens to an image sensor.
 32. The method of claim 30 further comprising configuring an additional reflective surface to remain a fixed distance from only one of the reflective surfaces during the scanning.
 33. The method of claim 30 further comprising configuring at least one of an image sensor and the lens to remain fixed relative to the driven one of the reflective surfaces. 